Concrete blocks intended to serve as wall blocks (e.g., retaining wall blocks), column blocks, step blocks or other types of structural blocks are sometimes provided with a natural stone appearance over an exposed portion thereof. Such concrete blocks can then be assembled into walls, columns, steps or other structures that have a natural and aesthetic look.
While various configurations, sizes and looks exist, these concrete blocks are conventionally monolithic elements made of various types of concrete. This monolithic character often detrimentally affects versatility of existing concrete blocks and their capability to accommodate design constraints of structures to be constructed.
Also, depending on their constituent concrete, concrete blocks can be broadly divided into dry-cast concrete blocks and wet-cast concrete blocks. Different processes are used to manufacture these two types of concrete blocks and, in particular, to provide them with a natural stone appearance.
Wet-cast concrete blocks may have a natural stone appearance realized directly during casting, but relatively long production times and requirements for numerous molds typically render impractical their efficient mass-production. For their part, dry-cast concrete blocks normally have relatively short production times and require only one or a few molds, which facilitates their mass-production. However, these relatively short production times impose constraints on a degree of surface irregularity that may be imparted to dry-cast concrete blocks during casting, thereby preventing realization of a natural stone appearance during casting. Dry-cast concrete blocks are thus typically subjected after casting to a mechanical artificial aging/weathering process (e.g., tumbling, splitting/breaking, object impacting, etc.) to realize desired natural stone characteristics, which decreases production efficiency.
There is therefore a need for improvements in concrete blocks, in particular those with a natural stone appearance, that may be used in walls, columns, steps and other types of structures.